Someone, please tell me this is a bad idea...


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barnbwt
April 29, 2012, 10:50 PM
Update: Yeah, it's a bad idea...
I recently bought a K31, which shoots a funny 7.5mm Swiss round that is as close as possible to .308 without being compatible. Anyway, I bought a box of FMJ-BT PRVI ammo to sight in the rifle with, only to realize my local gun range prohibits the use of FMJ (let's not get into the wisdom of that):cuss:. Though I believe Wolff makes a soft point variation, the vast majority (and some of the best) of ammo out there for this caliber seems to be FMJ.

My question is; is there any way to convert the FMJ I have to "soft point" by removing a small amount of metal right at the tip of the round:uhoh:? I am not attempting to "improve expansion" or anything, just removing the very tip so it is not technically FMJ by the range's standard. I'm sure this would screw with accuracy somewhat, but if the bullet can still operate safely, I'd be able to at least do some <100yd shooting to get a feel for this very cool carbine.

If not, I intend to pull these bullets and seat new HPBT ones (at least the .308 bullet-seating die is compatible with 7.5 Swiss). Would there be any particular set-back issues I need to keep in mind when doing this, or can I just simply replace the factory 174gr bullet with a 175gr Matchking, making sure the OAL is proper for the standard cartridge? Would I also need to re-charge the cases as well? Hopefully someone with K31-specific experience can chime in.

Thanks for the help, I hope I've been humble enough in asking my stupid question... :o

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TurtlePhish
April 29, 2012, 10:56 PM
Removing metal at the tip will probably ruin the accuracy that the gun is capable of, but it's not gonna blow up or anything. Back in WWI some bullets from Mauser cartridges were pulled and reseated backwards so they would hit tanks and cause spalling instead of penetration to the inside.

Edit: If anyone doubts that, http://en.wikipedia.org/wiki/Reversed_bullet

snakeman
April 29, 2012, 11:11 PM
don't do it. As most of these bullets are cup and core in which the cup is open at the base of the bullet you may cause the core to migrate trough both ends of the jacket.

R.W.Dale
April 29, 2012, 11:24 PM
don't do it. As most of these bullets are cup and core in which the cup is open at the base of the bullet you may cause the core to migrate trough both ends of the jacket.

This is the correct answer.

A FMJ bullet is in a sense nothing more than a SP bullet with the exposed lead at the bullet base instead of the tip.

If you open the bullet tip up then you have exposed bullet core at both ends introducing the very real possibly of the bullet core "squirting" out of the jacket and leaving it behind in the bbl as a bore obstruction.

Bore obstructions blow guns up.

Tommygunn
April 30, 2012, 12:25 AM
My father once told me it was not uncommon for those armed with M-1 Carbines to impress, or cut, an "X" into the nose of the .30 carbine round. This helped make it into what was called a "dum-dum" round. The carbine round was reputedly a weaker round -- well, certainly weaker than the .30-'06 and by making it into a sort of field-expedient dumdum it made it a better performer ... or so goes the theory.
The core would not "squirt" through leaving a barrel obstruction. However there is no point in doing this today as you can get real hollowpoint .30 carb. rounds that will legitimatly mushroom, so I will not advise you to try it .... just to play it safe.

451 Detonics
April 30, 2012, 07:33 AM
Anyone who has shot a Hakim will attest to how recoil free these rifles are for such a heavy caliber (8mm). I mounted a red dot on one and tried it for bowling pins but the military FMJ rounds tended to zip through without clearing the pin off the table. I started cutting about 1/4 inch off the tip with a pair of sidecutters and suddenly I was blowing pins halfway up the backstop. I used this rifle and ammo combo to win quite a few pin matches. Accuracy at that range was not really an issue and I never had a problem with core/jacket separation.

Brian Williams
April 30, 2012, 09:40 AM
I never had a problem with core/jacket separation.
yet

303tom
April 30, 2012, 12:22 PM
A FMJ means just that (Full Metal Jacket) it probably won`t hurt any thing, but if they are lead core why not just do this. Take a Dremel & drill a 1/16 x 1/8 inch hole in the tip like this, they work great...........These are 7.5 French.

jason41987
April 30, 2012, 12:28 PM
umm.. suprised no one suggested pulling the old bullets and seating different ones... if its hard to find ammo for the rifle you should get reloading gear for it anyway... thats what id do

Vaarok
April 30, 2012, 12:31 PM
Pull a projectile from your preferred brand, if it's jacketed to include the base, go ahead and perforate the nose. If it's lead-base, it's not recommended.

Theoretically, this is all not only possible, but a traditional solution- there are numerous articles in the fifties about how to do it to GI ammo for hunting with a drill-press, and ten thousand times as many stories from old guys.

HOWEVER, you do this ENTIRELY at your own risk, and it is potentially very dangerous. If you are cognizant of the danger and choose to do so, you do it aware of the risks and accepting of them.

Carl N. Brown
April 30, 2012, 12:54 PM
Pull some full metal jacket (FMJ) bullets: the nose has a full metal jacket, the base (on all those I have handled reloading pulled military bullets) have had exposed lead core at the base.

Cutting of the nose of the jacket or drilling a hole in the jacket creates a tube of jacket metal holding a lead core.

FMJ military rounds have a jacket closed at the nose, open at the base (they are NOT Total Metal Jacket TMJ).
Jacketed Soft Point JSP hunting rounds have a jacket closed at the base, open at the tip.

Lead core will not blow out of a FMJ or JSP; it can blow out of a FMJ with the nose compromised. You are betting on the bond between the lead core and the jacket holding fast under 40,000 to 55,000 psi when you compromise the nose of a FMJ bullet.

R.W.Dale
April 30, 2012, 01:46 PM
There's a lot of misinformation being posted here by folks who I can't help bus suspect have never seen a FMJ component bullet.

The pic below shows what military FMJ bullets look like at the base.

http://1.bp.blogspot.com/_f1TTfqxVUw4/TC58555JCII/AAAAAAAABhA/XaCvLuqAWMw/s1600/FA+173+FMJ.JPG

shotgunjoel
April 30, 2012, 02:11 PM
I know that this was done to 7.5 French surplus ammo sold in Germany (FMJ is evil in Germany), never heard if it caused problems besides loss of accuracy.

barnbwt
April 30, 2012, 11:25 PM
Thanks for the advice, guys. I figured this was a bad idea, just wanted to make sure I wasn't missing out on a cheap and easy hack. I once thought pulling "dangerous, live bullets" was foolhardy, too, that's why I come here to learn:). I'll buy a bullet-puller and seat the new bullets in my press.

That said, from the research I've done on the old forums here, elsewhere(box o' troof), and from your responses, the general consensus is:

DON"T DO IT (to the Internet's credit, I found this out very quickly)

It's an unecessary addition of risk for very little reward. Accuracy is trashed, debris can be left in the barrel, and expansion (though not my motive) is not improved well. It sounds like there is little to no risk in removing the very tip, making only a pin-hole in the tip of the jacket, but the round would still perform like an FMJ. For that reason, a filed FMJ flat point is probably still banned at the range (FMJ's bounce over the tops of berms, or something). It would be nice I could do something with these very nice bullets besides giving them away, though.

My next question, is how to go about replacing these. It looks like there is a Sierra Matchking .308 with very similar weight (175 vs 174gr) and profile, is it safe to simply stack it atop the existing powder once the old slug is removed?

(side question: these Matchkings are closed at the base, and open only at a tiny hole at the tip. How the heck do they swage the core into these with both ends effectively closed?)

Thanks again,
TCB

Float Pilot
April 30, 2012, 11:55 PM
A local guy who is my most pressing competition during the local Mauser Match shoots a K-31 which he soft loads with gas checked cast lead bullets. He has almost beat my Swede Mausers a couple times over the years.

(side question: these Matchkings are closed at the base, and open only at a tiny hole at the tip. How the heck do they swage the core into these with both ends effectively closed?)

P.F.M.

ExAgoradzo
May 1, 2012, 11:46 AM
1. Why on earth would the range outlaw FMJ? This is a serious question, I really don't know unless it is the lead that they are worried about; and a range that only allowed copper would soon go out of business!

2. I read the wiki article. I didn't for a sec doubt the truth of what you said, but I also noted the popularity of the bullet from the infantry! LOL!

barnbwt
May 1, 2012, 11:53 AM
The range is currently dealing with a lawsuit, and there insurance is probably making them ban fmj as a cya. Apparently fmj bullets don't deform enough and can bounce over the top of berms that aren't steep enough. Some fmj is also steel core and is rougher on backstops. My range should really just pony up for a rental bobcat and make the berms a few feet higher, instead of pissing off their customers. Nearly all ranges around DFW are anti fmj.

TCB

ExAgoradzo
May 1, 2012, 05:31 PM
The range is currently dealing with a lawsuit, and there insurance is probably making them ban fmj as a cya. Apparently fmj bullets don't deform enough and can bounce over the top of berms that aren't steep enough. Some fmj is also steel core and is rougher on backstops. My range should really just pony up for a rental bobcat and make the berms a few feet higher, instead of pissing off their customers. Nearly all ranges around DFW are anti fmj.

TCB
"The range is currently dealing with a lawsuit, and there insurance is probably making them ban fmj as a cya. Apparently fmj bullets don't deform enough and can bounce over the top of berms that aren't steep enough. Some fmj is also steel core and is rougher on backstops. My range should really just pony up for a rental bobcat and make the berms a few feet higher, instead of pissing off their customers. Nearly all ranges around DFW are anti fmj. TCB"

Thanks.

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